Chelsea are looking to force a passage beyond Benfica on Wednesday into the semi-finals of the Champions League, where they would face Barcelona, the holders and conquerors on Tuesday of Milan. Their Brazil midfielder Ramires has praised Roberto Di Matteo for restoring confidence and belief in the squad following André Villas-Boas' traumatic tenure at the club.

The London club secured an impressive 1-0 victory at the Estadio da Luz last week to stand on the brink of a sixth Champions League semi-final in nine seasons, and their first since 2009, ahead of Wednesday's return fixture at Stamford Bridge. Di Matteo's team are the last remaining English side in European competition while Saturday's victory at Aston Villa left them five points off third place in the Premier League with an FA Cup semi-final against Tottenham Hotspur still to come.

Form and confidence have steadily been restored over the past four weeks since Villas-Boas was dismissed barely eight months into a three-year contract and the squad are now apparently united behind the interim manager's approach. "We went through a tough period, obviously, but have taken strength from this change in the coach," said Ramires, one of the few players to have excelled under Villas-Boas and arguably Chelsea's player of the season. "We have found great confidence after that change, feeling more respect in ourselves.

"Roberto has brought in some new ideas and instilled great confidence in us all. It's difficult to explain the change in our fortunes but we have begun to realise we are a great team with great players and have built from our first victory under him [in his first game, against Birmingham City in the FA Cup] and simply gone from strength to strength."

Di Matteo, whose contract as a first-team coach is due to expire at the end of June, had not been considered a long-term candidate to succeed Villas-Boas despite enjoying success at his previous clubs, MK Dons and West Bromwich Albion, and his status as a former favourite at this club. Yet, while he remains a distinct outsider to take on the position full-time, admiration is building within the hierarchy at the job he has done in trying circumstances. Chelsea's campaign had appeared to be unravelling under Villas-Boas, with dissent having erupted in the dressing room at his methods.

In contrast Di Matteo's more diplomatic approach has been welcomed even by fringe players and the mood within the squad has improved beyond recognition. "The fact that we are winning also helps," said the manager, who has no major injury concerns ahead of the second leg. "That helps improve the confidence within every major player and within the group. There are players who, maybe, haven't had many chances or hadn't played as much but who are now getting more game-time and expressing themselves at a very good level.

"We are a team and have to behave like a team. And stability helps every player and every club. The players know that they have to perform and that they have a responsibility towards themselves and the club. We just have to try and get the best out of them. That's the way it is."

The Italian has made no secret of his desire to return to management in the future – he was dismissed at The Hawthorns midway through last season having gained promotion from the Championship – though he has declined to comment publicly on his prospects of securing the position full-time. "I'm very happy to be the temporary coach and I want to win as many games as I can," he said. "This is a fantastic club but I just need to win games. That's all that matters."

The stand-in has already overseen one eye-catching home victory over Napoli in this competition during his short spell in charge, together with last week's encouraging – and rare – away success at Benfica, when what had appeared a bold team selection paid off handsomely. Only two teams have failed to progress in this re-vamped competition after winning the first leg away from home but Di Matteo will stress the need to guard against complacency before sending his team out against the Portuguese.

"That first leg win was a dangerous result," he added. "This is half-time and we're leading but a 1-0 lead is basically nothing. Our players are aware of this and we'll have to go into this game with the same attitude as we did against Napoli when we were 3-1 down. Nothing has been achieved yet. That is the kind of hunger we have to show in this match."